<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    /* #app{
      width: 400px;
      height: 400px;
      border: 1px solid #000;
    } */
    /* .box1, .box2, .box3{
      width: 100%;
      height: 100px;
      background-color: burlywood;
      margin-bottom: 10px;
    }
    h2{
      color: blueviolet;
    } */
    /* #app div{
      border: 2px solid #f50707;
    } */

    /* #app > div{
      border: 2px solid #f50707;
    } */
/* 
    .box1 + .box2{
      border: 2px solid #ea490e;
    } */

    /* #app .box2{
      border: 2px solid #ea490e;
    } */


    /* input[abc='abc']{
      border: 2px solid #f80303;
    }

    #input::before{
      content: '000';
      display: block;
    }

    #input:focus{
      background-color: #e38787;
    } */
  </style>
  <style>
    #box{
      width: 200px;
      height: 200px;
      background-color: aquamarine;
    }
    .wrap{
      background-color: rgb(227, 80, 47);
    }
    div{
      background-color: rgb(46, 38, 202);
    }

    
  </style>
</head>
<body>
  <!-- <div id="app">

    <div class="box1">
      <div class="title">
        <h2>这是标题</h2>
      </div>
    </div>

    <div class="box2"></div>

    <div class="box2"></div>

    <div class="box3"></div>

  </div> -->
  <!-- <input type="text" abc="abc">
  <input type="text" id="input"> -->

  <div id="container"></div>

  <div id="box" class="wrap">
    hello world
  </div>

</body>
</html>